Casting apparatus



Sept. 23, 1958 M. H. POND 2,852,821

CASTING APPARATUS Filed 1390.20, 1954 2 Sheets-Sheet 1 INVENTORZ MARVINH. POND A TTORNEY Sept. 23, 1958 M. H. POND 2,852,321

CASTING APPARATUS Filed Dec. 20. 1954 2 Sheets-Sheet 2 INVENTOR.

MARVIN H. POND ATTORNEY United States Patent Ofifice 2,852,821 PatentedSept. 23, 1958 CASTING APPARATUS Marvin H. Pond, Hamden, Conn, assignorto Olin Mathieson Chemical (:orporation, Alton. Ill., a corporation ofVirginia Application December 20, 1954, Serial No. 476,397

11 Claims. (Cl. 22-574) This invention relates to the casting of metaland more specifically to an improved apparatus for continuously castingmetal.

One known method of continuous casting of metal and especially in ashape having a width far in excess of the thickness thereof. involvespouring and solidification of the metal between two broad. moving belts;and in apparatus for the practice of this method, it is necessary toprovide a suitable side wall structure of a height about the thicknessof the strip to be cast to confine the metal at the edges untilsolidification occurs. I-leretofore, various side walls have been tried.A stationary side wall structure, for example, is one type which hasbeen tried, but poor operation has resulted largely because of thefrictional resistance presented by this type of side wall to the metalbeing shaped. To overcome this problem moving side walls of varioustype: including laminated walls have also been tried; but penetration bythe molten metal and undesired welding between the s and the metal beingcast have prevented the suc.. sful ado tion of such structures and anyworthwhile rcution of the potential advantages of endless belt castinglTl'rlChillS. Most of these prior types of side wall structures havebeen further characterized by inubitity to adjust to variation in beltspacing and by diszulvantageous heat conductivity for the successfulcasting of metal in the shape of a thin slab or strip. Specifically adisadvantage of these prior art mold side walls has been the diflicultyof obtaining an operable fit at the edges of the broad moving castingbelts adjacent the side walls and especially the type of fit necessaryto prevent the escape of molten metal between the belt and side wall andto avoid the resultant inferior performance whenever excessive flash.for example, is formed by the escaping metal.

Therefore, one object of this invention is to overcome theaforementioned ditlicultics by provision of a side wall of novelconstruction. Another object is to provide improvements in a moving belttype continuous casting apparatus suitable for production of metal stripand the like. Other objects and the advantagesv this invention will beapparent from the following deacrlption and the accompanying drawing inwhich:

Figure l is a sen'lidiagrammatic elevational view showing a typicalmoving belt type of continuous casting machine having side walls inaccordance with this invention;

Figure 2 is a cross-sectional view taken on line ll-ll of Figure 1;

Figure 3 is a perspective view of a. part of one preferred embodiment ofthe side wall of this invention with an end shown in cross-section.

Figure 4 is a perspective view of a part of another embodiment of theide wall with an end shown in crosssection.

In accordance with this invention, there is provided, in a castingapparatus, compressible mold walls or an edge dam made up of a bundle ofrefractory fibers or strands and specifically of asbestos thread ortwine. The asbestos preferably is woven to form a fabric or sheetinterwoven with metallic strands and more specifically with thinflexible wire forming a reinforcing core in some and preferably all ofthe asbestos thread or twine. This sheet is laid up to form a laminatedbody, the plies of which are secured in any suitable way such as bystitching but preferably by stitching with a metal, asbestos, or otherrefractory strand. Thus by means of this: invention there is provided aflexible, compressible, and preferably reinforced, refractory edge damor mold side Wall structure characterized by the ability to adapt itselfto such spacing and spacing variation as normally occurs in the beltcasting machine. The side wall surface of this structure presented tometal being cast is capable of bearing and taking up a suitable molddressing compound in a satisfactory manner. But the side wall structureas such is capable of satisfactorily containing molten metal without acoating of any kind.

The compressible asbestos side wall structure is fibrous and preferablyporous so that whenever mold dressing is specified, it is also adaptedto pick up the mold dressing material in a desirable way. The fibrousside wall is not only compressible but also resilient to an appreciableextent so as to substantially resist early packing down and theresultant loss of porosity and compressibility. By porosity is meant thepresence of interstices which enhance the compressibility of the sidewall and facilitate the application of mold dressing to the side wallstructure. When compressed between face plates or belts of various typesof casting apparatus, the side wall structure of this invention providesa satisfactory mold wall. A suitable mold dressing may be readilyapplied as desired to alter the heat abstraction characteristics of thewalls to suit the particular metal being cast or the particular castingapparatus in which the side wall is being used.

For continuous casting apparatus of the kind described, the side wall isin the form of an endless belt constituted largely of asbestos strandsor fibers. Preferably the endless edge dam structure of this inventiontakes the form of a single convolutely wound piece of asbestos tape orribbon secured together as lamina of the structure. How ever, thelaminated structure may be formed of a plurality of pieces of ribbon ortape secured together in any suitable manner.

The preferred embodiment of the edge dam found to produce satisfactoryoperation of the belt type casting machine described consists of anendless, flexible, wirereinforced, woven asbestos tape of suitable Widthplied up to desired thickness and bound together by stitching withasbestos fiber cord or metallic thread to form a laminate. To thesurface of this compressible mold wall there is applied usually asubstantially heat resistant dressing at the surface exposed to themetal in the process of being cast. The laminated mold side wallstructure of this invention may also be impregnated throughout with arefractory parting and mold dressing material such as one includinggraphite or the like. A suitable dressing, especially for casting ofaluminum, is one made up of a silicone, silica gel and graphite. Otherdressings and parting compounds suitable for the casting of metal may,however, also be used such as colloidal graphite in lard oil and thelike. A suitable silicone for the purpose is dimethylpolysiloxane. Thenature of the dressing however, is not of importance since its use andits type is purely optional with the casting machine operator.

The invention will be better understood from and illustrated but notlimited by a reference to the rather diagrammatic representation ofFigures 1 and 2 of a continuous casting machine in which 1 and 2 eachrefers to an endless side wall or edge dam belt of this inventionadapted to be sandwiched between endless broad metal mold face belts orbands 3 and 4 at the lateral edges thereof. Side walls 1 and 2 arecarried along on and adjacent the lateral edges of belt 3, which in turnis supported on and passes around end rolls and 6. The other maincasting or mold face belt 4, which like belt 3 is made of a strip ofsuitable metal such as stainless steel. is carried over another pair ofend rolls 7 and 8. As shown in Figure 2, belt 4 overlies belt 3 and inthe casting area of the machine belts 3 and 4 pass in closely spacedparallel relationship. Side wall belt 1 is carried about belt 3 at oneside of the rolls 5 and 6 while side wall belt 2 is carried at the otherside oi" rolls 5 and 6 about belt 3. in this casting area, the lowermold face belt 3 is backed up by a series of rolls 9 and upper mold facebelt 4 is in turn backed up by a series of rolls 19. As assembled inoperative relation ship in the casting area of the machine, side belt 1forms the edge dam 11 and belt 2 forms the edge darn ll f the castingcavity 13 of rectangular cross section defined by the mold face belts 3and 4 and the edge dams 1i and 12. At the masting cavity 13 the lateraledges of face belts 3 and 4 are pressed at intervals against the edgedams El and 12 by any suitable instrumentalities such as the series ofsupport rolls 9 and the ends of which arc forced against the back sideof the lateral edges of the face belts 3 and 4 so as to squeeze belts 3and 4 against the compressible edge dams 11 and 12, which are backed upby guide bars 14 and 15, respectively. Side belts 1 and 2 and face belts3 and 4 are driven by any suitable mechanism to move with the casting 18as it traverses the cavity 13.

In operation molten metal from reservoir or crucible 16 is supplied tothe tundish 17 which feeds a stream of metal at a desirable flow rateinto the cavity 13 in which solidification of the metal occurs toproduce the relatively broad thin slab 13. To aid in solidifying themetal. belts 3 and 4 may be subjected to a stream of coolant.

The side wall or edge dam structure according to the specific embodimentof Figure 3 consists of layers of asbestos ribbon or tape 19 having wirereinforcing 20 longitudinally or in the direction of the length thereofand which is bound together by parallel rows of stitching 21. Theasbestos tape 19 is woven from asbestos thread of a diameter of about0.0625 of an inch, for example, into which is twisted flexible metallicstrands 20 each of a diameter of about 0.008 of an inch and made up ofany suitable metal such as copper, brass, steel or the like. The tape 19is plied up to a suitable thickness to form the multiple layer endlessedge darn structures 11 and 12, all the layers of which are securedtogether by stitching with asbestos yarn 21. To form endless side wallbelts 1 and 2, tape 19 may be convolutely wound and then secured by theyarn or strand 2].

For the obtainment of maximum compressibility, this type of edge dam isinstalled so that the lateral edges 22 of the layers are presented toand confine the molten metal. Where the temperature conditions sorequire, a mold dressing material is applied to the face made up by thecontiguous edges 22 so that at least this face carries dressing.

The metal casting mold side wall of this invention may also take theform illustrated in Figure 4, wherein the asbestos cloth 23, as in theprevious embodiment, is firmly reinforced and supported by metallicstrands 24 and is further impregnated, if desired, with a siliconecompound such as one consisting of dimethylpolysiloxane, or withcolloidal graphite or silica gel particles. In this embodiment the sheetor fabric is convolutely wound laterally from both lateral edges so asto make up a plurality of layers. For a belt type continuous castingmachine the structure illustrated in Figure 4 may consist of a singlecontinuous wide loop or ring of such asbestos fabric or sheetconvolutely wound laterally to present the narrow compressiblemulti-layer structure shown. It may also be formed by a convolutelywound wide tape given secondary convolute turns to reduce the width andincrease the number of layers of asbestos sheets in the finished endlessside wall. Where necessary,

according to the dictates of the heat released, the mold dressingmaterial is applied to the face 25, which is next to the metal. so thatat least this face carries dressing.

Beside these two embodiments others can be made. For instance wirereinforced asbestos strand can be laid in parallel to make a bundlewhich may be enclosed in woven asbestos tubing.

One big advantage secured by this invention lies in the fact that theplied up refractory fabric structure coated with and even to some extentimpregnated with a suitable dressing provides a desirably high degree ofcompressibility of one unit enabling a positive seal to be made betweenthe two broad casting belts of the machine thereby preventing anyleakage of molten metal. The prior art moving edge dams have beendifficult to control because of their incompressible construction. Withthe side wall construction described herein it is also possible toattain a low value of heat conductivity which under some circumstancesis desirable to prevent abstraction of heat at the lateral edges of theshape being cast. It will be appreciated that friction between thecasting and the edge dam is not a factor in this type of side wallstructure. Another advantage secured by this invention is that when thecompressible endless side wall structure is impregnated with a flowablemold dressing, as the wall enters the bite of back-up rolls disposedalong the main casting belts and is compressed there is automaticallyexuded a fresh layer of dressing at the surface exposed to the metalbeing cast at times desired in the casting process.

While the invention has outstanding utility in the art of continuouscasting with respect to which it has been described herein, it will beunderstood that it has utility with any metal casting apparatus such asthe permanent metallic type of two part book mold.

Since many other embodiments may occur to those skilled in the art, itis to be understood that the foregoing is intended by way ofillustration and not as a limitation of the scope of the presentinvention except as set forth in the appended claims.

What is claimed is:

I. In combination with machine for continuously casting wide thin shapesfrom molten metal having a pair of elongated moving casting bands ofmetal traveling in the same direction and at least over part of theirtravel in spaced facc-tofacc relationship. a compressible mold side wallat each opposed pair ofgthc lateral edges of said bands, said side wallsconsisting of multiple layers of asbestos fabric interwoven withmetallic strands and directly facing the molten metal.

2. In combination with a machine for continuously casting wide thinshapes from molten metal having a pair of elongated moving bandstraveling in the same direction and at least over part of their travelin spaced face-toface relationship, a compressible mold side wall ateach opposed pair of the lateral edges of said bands, said Wallconsisting of a bundle of asbestos fibers and metallic strands anddirectly facing the molten metal.

3. in combination with a mach ne for continuously casting wide thinshapes from molten metal between a pair of clongated moving broad metalbands traveling in the same direction and at least over part of theirtravel in spaced face-to-fnce relationship. a compressible mold sidewall comprising a moving belt etween each opposed pair of the lateraledges of said bands. of flexible asbestos sheeting and metallicstraruls. said sheeting and strands running in the direction of thelength and travel of said side wall and directly facing the moltenmetal.

4. ln apparatus for the casting of metals. a molten metal pressureretaining mold wall comprising a com pressible bundle consistingessentially of a contiguous plurality of strands laid up so as to eachextend substantially continuously in the longitudinal direction in saidmold Wall transversely to the direction in which said molten metalpressure is exerted in said wall and with limited mobility with respectto each other in said wall under a mold wall compressive force appliedtransversely both with respect to said longitudinal direction and moltenmetal pressure direction.

5. The apparatus of claim 4 wherein the strands consist largely ofasbestos.

6. The apparatus of claim 5 including metallic strands interwoventherewith.

7. The apparatus of claim 4 wherein the strands comprise asbestos tapeassembled in layers stacked together in the direction of the compressiveforce and with one set of contiguous lateral edges of said tape assemblyfacing in juxtaposition with respect to the molten metal.

8. The apparatus of claim 7 wherein the asbestos is in the form of acompressible woven fabric tape extending longitudinally with metal wirereinforcing interwoven in the tape.

9. The apparatus of claim 8 wherein the layers of tape are all securedtogether.

10. The apparatus of claim 7 wherein the tape is convolutely wound atleast in one of the longitudinal and transverse directions to be pliedup to form a mold side wall element of substantially rectangularcross-section to a heighth substantially l.l excess of the compressedheighth in said side wall.

ll. The apparatus of claim 10 having metallic strands interwoven in saidtape in the longitudinal direction.

References Cited in the file of this patent UNITED STATES PATENTS1,108,693 Burkhardt Aug. 25, 1914 2,193,429 McConnell Mar. 12, 19402,230,27l Simpson Feb. 4, 1941 2,372,673 Jacob Apr. 3, 1945 2,489,322Olsen Nov. 29, 1949 2,496,279 Ely et al. Feb. 7, 1950 2,554,548 AlbagnacMay 29, 1951 2,676,369 Stark Apr. 27, 1954 FOREIGN PATENTS 575,734 GreatBritain Mar. 4, 1946 383,313 Italy Oct. 2, 1940

